How Trauma Impacts the Brain: A Physiological Response to Stress

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Trauma is a word that we all have heard before, but what exactly is trauma? And if you have experienced a traumatic event, is recovery even possible?  

Trauma is the emotional, physical, and mental response to a tremendously stressful event.  This can include the death of a loved one, hospitalization, abuse, a natural disaster, or witnessing any distressing event that has a significant impact on your functioning. 

Despite your best efforts, trauma is something that you cannot “just get over”. It impacts functioning in many aspects of your life.  After a traumatic event, you might experience changes in sleep patterns, memory loss, strained relationships, an inability to trust, nightmares, or intrusive thoughts.  

In addition to these psychological changes, there are also significant trauma-induced physiological changes that take place in the brain and body. 

To understand the impact of trauma on the brain, let’s first discuss the basics of how your brain develops and changes over time. 

Brain Development

Your brain, while mostly formed in utero, is constantly changing throughout your life. 

  • From ages 0-5, brain volume increases through the development of both white and grey brain matter.  

Grey brain matter is where your brain processes information.

White brain matter provides the communication between the areas of grey matter –  the messenger. 

  • From ages 7-17, there is an increase in white matter and a decrease in grey matter.  The frontal cortex develops greatly during this time. The hippocampus and amygdala increase in size. 

  • From ages 20-70, there is a gradual decrease in grey matter.  Significant hormonal changes such as menopause impact the brain’s circuits and patterns. 

The key takeaway from learning about brain development is this — your brain is ever-changing and adaptable to your environment.  Neuroplasticity refers to the ability of the brain to make new connections. You can form new ways and pathways of thinking. 

Through neuroplasticity, you can rewire your brain. 

The Impact of Trauma on the Brain 

Research shows that trauma and stress change the brain’s neurochemical systems – the patterns and the circuits through which the brain releases hormones. Over time, trauma can also lead to changes in brain structure.   

Studies suggest that trauma impacts 3 main parts of the brain – the amygdala, hippocampus, and prefrontal cortex.  These 3 areas of the brain play critical roles in emotional regulation and fear responses – making it easy to understand how people’s lives are significantly altered after trauma. 

  • Increased function of the amygdala

    • The amygdala plays an important role in emotions, sensing fear, and emotionally-charged memories.

    • When your amygdala senses a threat to survival, it triggers a response designed for survival, to keep you alive – called the fight, flight, or freeze response. It is often triggered by emotions such as fear, aggression, anger, or anxiety.

    • In times of severe stress or trauma, the response of the amygdala is likely to jump over the rational processing system of the frontal cortex, causing an extreme response for your survival. This can lead to irrational emotions or reactions.

    • Trauma causes the amygdala to be hyperactive and continuously “on” as if there is an ongoing threat present – even when there may not be. 

  • Smaller Hippocampus

    • The hippocampus, a part of the limbic system, is responsible for learning and memory functions. 

    • The hippocampus is the part of the brain that helps you decipher between past memories and current events, such as what is going on right now.  

    • After trauma, the hippocampus appears to be smaller in size– thus causing issues with understanding the difference between past and present. 

    • After a traumatic experience, studies show that things that happened in the past are experienced as presently ongoing. 

  • Decreased function of the prefrontal cortex

    • The prefrontal cortex plays an important role in the regulation and control of your emotions and impulses. 

    • After trauma, you may be less able to control fear and reactivity as the survival areas of your brain have overruled your rational ability to control them. 

Your brain’s circuits also control the release of hormones throughout your body.  Trauma impacts the regulation of 2 main stress hormones, cortisol and norepinephrine. 

  • Increased cortisol production

    • Produced during times of stress 

    • Increases levels of sugar in the bloodstream

    • Halts non-essential bodily functions 

    • Chronically high levels of cortisol can lead to heart disease 

    • During trauma, cortisol activates the fight, flight, or freeze response

  • Increased norepinephrine production

    • Increases heart rate and contributes to the survival response

    • After trauma, this can add increase your fear response and cause you to feel continuously threatened

Those that have experienced trauma may develop symptoms of post-traumatic stress disorder (PTSD).   PTSD affects about 8% of Americans and often occurs after a significant traumatic event or series of events. 

PTSD is characterized by:

  • Intrusive thoughts

  • Sleep issues

  • Heightened arousal

  • Flashbacks 

  • Problems with memory and concentration

  • Changes in startle responses

Prognosis and Treatment for Trauma

There is good news.  Because of the neuroplasticity of the brain, you can rewire and normalize the areas of your brain affected by trauma. Your brain is ever-changing. You are learning and growing.  There is hope for you. 

Research suggests that, with treatment, you can: 

  • Increase hippocampus function 

  • Improve memory 

  • Reinforce the abilities of the prefrontal cortex for greater emotional regulation

  • De-activate your amygdala to return to a normalized state 

  • Return to normal levels of stress hormones for better sleep and less agitation, fear, and worry 

Therapy can help you increase mindfulness and awareness of how your body responds to stress and trauma. Consult with your doctor to see if you are a good candidate for psychopharmacologic and somatic therapy that may help.  

You can learn how to form new brain connections that facilitate the creation of the healthy and whole life that you desire. 

Trauma does not have to be the end of your story – healing is possible. 

If you would like more information on how to overcome your trauma and stress, check out my online course. 

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